# 百度云，输入密码   _  _  _  _
import itertools
mylist = (["".join(x) for x in itertools.product(
    "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ", repeat=4)])
print(mylist)
print(len(mylist))
